This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. The persistence of viral reservoirs and chronic immune activation pose major challenges for achieving complete immune recovery in HIV infected patients, even during long-term therapy. The frontline mucosal immune defenses are crucial in preventing and limiting HIV infection and controlling spread of enteric pathogens and microbial translocation. HIV causes breach in the mucosal defense leading to colonization and microbial translocation of enteric and luminal microbes. This contributes to chronic immune activation and immune dysfunction in HIV infection and supports viral persistence, although mechanisms have not been fully defined. The proposed studies will investigate HIV induced dysfunction in the frontline gut mucosal responses to bacterial pathogens in the SIV infected rhesus macaque model and determine the mechanisms contributing to the inability of the host to control these infections. Gaining insights into the mucosal immune defenses critical in maintaining gut mucosal health will be crucial in identifying therapeutic targets for mucosal protection against the virus and co-infections.